The Vega visualization in Kibana supports both Vega and Vega-Lite. You can use the
schema value to define which language you would like to use and its minimum
schema URL is only used for identification, and does not need to be accessible by Kibana.
Vega-Lite is a simplified version of Vega; it automates some constructions and has much shorter specifications than Vega. Vega-Lite is automatically converted into Vega before rendering, but it has some limitations, and there are some visualizations that can be expressed in Vega that cannot be expressed in Vega-Lite. You can learn more in the Vega-Lite documentation.
You can use this editor to convert Vega-Lite into Vega.
When you create a Vega visualization in Kibana, you can edit the
value in the dev tools to the left of the graph to define which of the two expression
languages you would like to use (see examples above).